1. Field of the Invention
The present invention relates to a switch for vehicles, which is used for controlling the turn-on/off of a stop lamp when operating a brake pedal of a vehicle.
2. Description of the Related Art
Recently, a pressing-operation-type switch for vehicles is frequently used for controlling a stop lamp in accordance with the operation of a brake pedal. Specifically, the switch for vehicles turns on the stop lamp when the brake pedal is stepped on, and turns off the stop lamp when the brake pedal is not stepped on.
Such a conventional switch for vehicles will be described with reference to FIGS. 5 and 6.
FIG. 5 is a cross-sectional view of a conventional switch for vehicles. In FIG. 5, case 1 is formed in a box shape of which the top surface is opened and is formed of insulating resin. Operating body 2 is housed in case 1 so as to vertically move. Further, operating body 2 has magnet 3 mounted on a lower left side surface thereof.
A plurality of terminals 4 are formed of conductive metal. Wiring substrate 5 has a plurality of wiring patterns (not shown) formed on the right and left surfaces thereof. Wiring substrate 5 is disposed at the left side wall of case 1, and the upper ends of terminals 4 are connected to the wiring patterns of wiring substrate 5 by soldering or the like. Further, the lower ends of terminals 4 project downward from the bottom surface of case 1.
Wiring substrate 5 has detection device 6 such as a hall element and switching device 7 such as a power transistor formed on one surface thereof facing magnet 3. Further, control device 8 composed of a FET and a plurality of fixed resistors is formed on the surface of wiring substrate 5. Detection device 6 and switching device 7 are connected to control device 8.
Cover 10 formed of insulating resin covers the opening portion of the top surface of case 1. Further, coil-shaped return spring 9 is mounted in such a state where it is bent between the lower surface of operating body 2 and the bottom surface of case 1. Return spring 9 biases operating body 2 upward, and the upper end of operating shaft 2A of operating body 2 projects upward from hollow cylindrical portion 10A formed in the center of the top surface of cover 10.
FIG. 6 is a side view of essential parts of a brake pedal using the conventional switch for vehicles. In FIG. 6, conventional switch 12 for vehicles constructed in the above-described manner is mounted in front of brake pedal 13 of a vehicle in a state where operating shaft 2A of operating body 2 is pressed by arm 13A. Further, the plurality of terminals 4 projecting from the bottom surface of case 1 are connected to a stop lamp, an ignition switch, a battery and so on through connector 14 and lead wires.
In a state where brake pedal 13 is not stepped on, operating shaft 2A of operating body 2 is pressed downward while bending return spring 9, and magnet 3 mounted on the left side surface of operating body 2 is moved downward. Then, the center of detection device 6 disposed to face the center of magnet 3 is significantly separated from each other, and the magnetism of magnet 3 which is detected by detection device 6 decreases.
Control device 8 connected to detection device 6 controls switching device 7 based on the magnitude of the magnetism (magnetic flux density) detected by detection device 6. That is, when the magnetic flux density is equal to or more than a predetermined value, control device 8 switches switching device 7 into a close state. When the magnetic flux density is less than the predetermined value, control device 8 switches switching device 7 into an open state. Accordingly, in a state where operating body 2 is pressed, switching device 7 is set in the open state, and the stop lamp is turned off.
When brake pedal 13 is stepped on, arm 13A is separated from operating shaft 2A such that the pressing force is canceled. Therefore, as shown in FIG. 5, operating body 2 is moved upward by the elastic restoring force of return spring 9. Then, magnet 3 mounted on the left side surface of operating body 2 is also moved upward in such a manner that magnet 3 and detection device 6 face each other. Accordingly, the magnetism of magnet 3 which is detected by detection device 6 increases. Then, control device 8 switches switching device 7 into the close state, and the stop lamp is turned on.
In the above-described operation of brake pedal 13, when a vehicle is stopped in a place where a following vehicle is present, and if brake pedal 13 is stepped on, the stop lamp needs to be turned on, even in a state where the ignition switch is turned off so as to stop the engine.
Therefore, in the conventional switch for vehicles, even when the ignition switch is turned off so as to stop the engine, power is always supplied from the battery to detection device 6 which detects the magnetism of magnet 3 and control device 8 which switches switching device 7 so as to turn on/off the stop lamp. Accordingly, the stop lamp can be turned on.
As the related art document related to the invention of the present application, Japanese Patent Unexamined Publication No. 2006-92777 is known.
In the conventional switch for vehicles, however, even when the ignition switch is turned off so as to stop the engine, power is always supplied from the battery to detection device 6 and control device 8 such that the stop lamp can be turned on when brake pedal 13 is stepped on. Specifically, a current of about 3 mA always flows. Therefore, the consumption of the battery occurs during this term.